ABB AC 800F, Инструкция по монтажу и установке

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4 Cabling the AC 800F
4-27
4.2.8.2 Linking 10Base5 cable segments
Several short 10Base5 cable segments can be linked by 10Base5 N/N connectors
until reaching the maximum length. The following standardized 10Base5 network
cable lengths are available:
•
23,4 m
•
117 m
•
500 m
•
70,2 m
•
257,4 m
The standard lengths specified above result from physical laws and have no logistic
reasons. Observe the following rules when deciding upon the cable lengths you want
to use:
1. Use one of the standardized cable lengths listed above.
If you need, for example, a 230 m 10Base5 network cable you should use a
257.4 m cable. Wind up the remaining cable length you don’t need. The advantage
of this solution is that the cable consists of a single piece. No errors can result from
defective cable joints.
Under certain conditions, however, the solution given above is uneconomic. If you
need, for example, a 400 m 10Base5 cable, there would be a surplus length of 100 m
when a 500 m cable is used. The following alternative solutions are possible:
2. Link several standardized cables until achieving the desired length
Link the following standardized cables to achieve a 400 m network cable:
23.4 m
23.4 m
117.0 m
257.4 m
____________________
Sum
421.2 m
The cables should be from the same manufacturer and production lot
(if possible).
The advantage of this solution is that the cable consists of standardized segments.
The disadvantage is that this cable is less reliable than a single-piece one, due to the
cable joints. Therefore, the 3rd alternative described below should be preferred.
3. Ready-made cables in customized lengths
Ready-made cables in lengths specified by the customer are available on request.
It is recommended to order cable lengths which are a multiple or a combination of
the standardized lengths listed above (for example, you should order 421.2 m
instead of 400 m, see example given in solution 2). This will enable future
expansions.